<?php
/**
 * User: lie
 * Date: 2020/11/5 10:10
 * description: 可变变量。双$符号意味着，第一次$输出str_name_1，第二次$输出str_name_1 等于 $str_name_1 = "I like PHP";
 */
$str_name = "str_name_1";
$str_name_1 ="I like PHP";
echo $$str_name;
